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Zimmerman (near junction of Twin and Pedro Creeks)

Prospect in Alaska, United States with commodity Gold
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Geologic information

Identification information

Deposit ID 10002905
MRDS ID A015394
Record type Site
Current site name Zimmerman (near junction of Twin and Pedro Creeks)

Geographic coordinates

Geographic coordinates: -147.47406, 65.01856 (WGS84)
Relative position Cobb (1972, MF-413), loc. 31; SW1/4NW1/4 sec. 12, T. 2 N., R. 1 E., of the Fairbanks Meridian. This prospect is 1/4 mile northeast of the mouth of Twin Creek. Accuracy is within 1,000 feet.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Gold Primary

Materials information

Materials Type of material
Arsenopyrite Ore
Gold Ore

Alteration

  • (Local) The schist in the vicinity of the Zimmerman prospect is silicifed, and some schist fragments carry a peculiar greenish-yellow stain (Hill, 1933).

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
  • Host or associated Host
    Rock type Metamorphic Rock > Schist

Nearby scientific data

(1) -147.47406, 65.01856
ListMap

Comments on the geologic information

  • Geologic Description = Hill (1933) visited the site and the following geologic description is a summary of his observations. Extensive exposures of mineralized quartz diorite and schist occur in a hydraulic cut on the Zimmerman property. Near the southwest or lower end of the cut, a fault zone strikes east and dips 85 N. The fault zone consists of 11 feet of blue clay gouge that contains a large amount of fragmental quartz and silicified schist. Some of the fragments contain arsenopyrite and have a peculiar greenish-yellow stain. A few samples from a 3-foot zone of silicified mineralized schist contained as much as 0.08 ounces of gold per ton.? Northeast of the gouge, the rock is quartz diorite. For seven feet above the fault, the diorite is badly crushed, but farther to the northeast, it is less altered, breaks in blocky forms, and is cut by several minor fault fractures that strike from west to N 60 W. Southwest of the main fault, the rock is highly silicified schist with many quartz veinlets and everywhere contains a small amount of finely disseminated arsenopyrite. The rock is bluish gray, hard, and heavier than the nomal quartz-mica schist. For at least 70 feet south of the main fault, this rock is broken and crushed, and there are several well-defined slip planes that vary in strike from N 70 W to west and dip north, all roughly parallel to the main fault.? the samples of the altered quartz diorite north of the fault contained neither gold nor silver. The silicified mineralized schist south of the fault carried only a trace of precious metals except for a few samples from a 3-foot zone that contained as much as 0.08 ounces of gold per ton. The gold-bearing samples contained notable sulfides (Hill, 1933, p. 118-119).

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Fairbanks

Comments on the workings information

  • Workings / Exploration = Surface samples were taken from a hydraulic cut (Hill, 1933).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A015394
USGS Alaska Resource Data File ARDF LG070

Bibliographic references

  • Deposit

    Hill, J.M., 1933, Lode deposits of the Fairbanks District, Alaska: U.S. Geological Survey Bulletin 849-B, p. 29-163.

  • Deposit

    Chapman, R.M., and Foster, R.L., 1969, Lode mines and prospects in the Fairbanks district, Alaska: U.S. Geological Survey Professional Paper 625-D, 25 p., 1 plate.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Circle quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-633, 72 p.

  • Deposit

    Cobb, E.H., 1976, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Livengood quadrangle, Alaska: U.S. Geological Survey Open-File Report 76-819, 241 p.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Livengood quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-413, 2 sheets, scale 1:250,000.

Comments on the references

  • Primary Reference = Hill, 1933

General comments

Subject category Comment text
Deposit Model Name = Auriferous, silicified schist.

Reporter information

Type Date Name Affiliation Comment
Reporter 04-MAY-1999 C.J. Freeman Avalon Development Corporation
Reporter 04-MAY-1999 J.R. Guidetti Schaefer Avalon Development Corporation